Efficient synthesis of bolaform- and gemini-type alkyl-bis-[(α-amino)phosphonocarboxylic or phosphonic acid] surfactants

The synthesis of a new series of bolaform- and gemini-type phosphorus acid surfactants is described. The Pudovik addition reaction of P–H bond tetraoxyspirophosphoranes to symmetrical, prochiral bis-imines bearing different more or less long and rigid linkers occurs instantaneously at room temperature. This reaction is diastereoselective and quantitatively leads to the corresponding alkyl-bis-[α-aminospirophosphoranes] in good to high diastereomeric ratio. Selective and one-pot hydrolysis of these P∗–C∗ bond bis-spirophosphoranes can be readily achieved either at room temperature by moist solvents giving the corresponding alkyl-bis-[α-aminophosphonocarboxylic acid] amphiphiles, or by a more drastic reaction of 20% aqueous hydrochloric acid under reflux affording free alkyl-bis-[α-aminophosphonic acid] surfactants in good yields.